The conventional rocking rod suffers form the following defects:
(1) The circuit system for controlling the direction of the rocking rod always uses imported electronic parts and the manufacturing procedure is more complicated; therefore, the manufacturing costs are increased.
(2) In the conventional structure, only a combination of the rocking rod and fixed rin 2 is present; there is no setting ring. That will not permit prolonged useful operation. Therefore, after long periods of use a gap will develop between the rod and the central hole of the final ring. Accordingly, the structural relationship and fit between components becomes non-conforming due to the friction of automatic rotation, and thus user can no longer enjoy the use of an accurate control effect.
(3) In the conventional device, the fixed ring of the rocking rod is made of hard material and does not possess elasticity. After the force applied to the handle is stopped, the device (rod) does not automatically return to the original place. The operator feels the control is stiff during use.
(4) The control key associated with the conventional rocking rod is always a single key; this makes both a left-handed or right-handed operator feel uncomfortable during operation. If the force applied to the key is over-loaded, damage will result to the key.
(5) The rocking rod is direct contact type, therefore, it is easy to wear down and lacks precision.